neumann@FUNCTION.MPS.OHIO-STATE.EDU ("Walter D. Neumann") (03/15/91)
\midinsert still has unresolved problems, which I will report on,
hopefully with solution, soon. In trying to fix it I ran into a
stupid debugging problem in trying to see why a \removelastskip
was not removing the last skip. If I define
\def\t{\immediate\write16{\the\lastskip}}
and then tex "\medbreak\t\medbreak" with \tracingall,
I see that the \t tells me that \lastskip is 0.0pt between the
two medbreaks, while the text \ifdim\lastskip<\medskipamount
inside the second \medbreak yields "false" (as it should).
What am I understanding wrong?
--
Walter Neumann Email: neumann@mps.ohio-state.edu
Department of Mathematics neumann@ohstpy.bitnet
Ohio State University Fax: 614-292-3639 to Neumann, Math Dept
Columbus, OH 43210 Tel: (614)-292-4886(office) 292-4975(messages)Schoepf@SC.ZIB-BERLIN.DBP.DE (Rainer Schoepf) (03/19/91)
From: "Walter D. Neumann" <neumann@function.mps.ohio-state.edu>
\midinsert still has unresolved problems, which I will report on,
hopefully with solution, soon. In trying to fix it I ran into a
stupid debugging problem in trying to see why a \removelastskip
was not removing the last skip. If I define
\def\t{\immediate\write16{\the\lastskip}}
and then tex "\medbreak\t\medbreak" with \tracingall,
I see that the \t tells me that \lastskip is 0.0pt between the
two medbreaks, while the text \ifdim\lastskip<\medskipamount
inside the second \medbreak yields "false" (as it should).
There is some special treatment of vertical-type quantities
(like your \lastskip) within a \write. Try the following:
\def\t{\skip0=\the\lastskip\immediate\write16{\the\skip0}}
With this you get the correct value of \lastskip. If I remember
correctly, the problem with \write is that TeX is in a special
"no-mode" when it is processing the content of the \write, and
\lastskip can only be accessed reliably in vertical and horizontal
modes. The only way to find this out is to read TeX - the program.
I'm sorry---there are lots of things that are not in the TeXbook...
Dr. Rainer Schoepf
Konrad-Zuse-Zentrum ,,Ich mag es nicht, wenn
fuer Informationstechnik Berlin sich die Dinge so frueh
Heilbronner Strasse 10 am Morgen schon so
D-1000 Berlin 31 dynamisch entwickeln!''
Federal Republic of Germany
<Schoepf@sc.ZIB-Berlin.dbp.de> or <Schoepf@sc.ZIB-Berlin.de>
eijkhout@s41.csrd.uiuc.edu (Victor Eijkhout) (03/20/91)
Schoepf@SC.ZIB-BERLIN.DBP.DE (Rainer Schoepf) writes: >There is some special treatment of vertical-type quantities >(like your \lastskip) within a \write. Try the following: > >\def\t{\skip0=\the\lastskip\immediate\write16{\the\skip0}} > >With this you get the correct value of \lastskip. If I remember >correctly, the problem with \write is that TeX is in a special >"no-mode" when it is processing the content of the \write, and Note that with \spacefactor and \prevdepth there are the same sort of problems, but there you get an error message. Victor.